1. Field of the Invention
This invention relates generally to gas dehydration systems which utilize Wet/Dry glycol pumps and more particularly to an auxiliary system incorporated into the dehydration system for detecting loss of supply to the glycol pump and effecting shut-down of the glycol pump, thus preventing damage to the pump.
2. General Background
A great many gas dehydration systems utilize Wet/Dry glycol pumps such as that disclosed by U.S. Pat. No. 4,676,806. Although glycol pumps take many different forms, the most common is the PV series Kimray.TM., Glycol Energy Exchange Pump, Such pumps having wet and dry glycol outlets provide flow through the high pressure section of the pump. Dry glycol inlets and outlets provide flow through the low pressure section of the pump. Hence the pump has a first and second chamber separated by a moving piston so that flow occurs along the inlet and outlet flow paths by using energy available from the wet glycol. Systems utilizing such pumps as disclosed in U.S. Pat. No. 4,026,681 have no protection if inline filters, located between the reboiler and the pump, become fouled or insufficient level of glycol in the Reboiler occurs. Although not all dehydration systems utilize filters in the dry glycol circuit, it is considered prudent to do so. Since the pump is being driven by the energy from the high pressure wet glycol portion of the pump, the pump continues to run even when no dry glycol is flowing through the pump. This imbalance allow the pump seals to dry out and deteriorate, requiring expensive maintenance. Gas dehydration systems are often located at remote sites and are generally unmanned. Therefore, when the glycol pump is not functioning the system is also malfunctioning, thereby causing critical problems which can become hazardous. It is therefore essential that the system be shut down as soon as possible when a problem occurs.